io.netty.handler.codec.compression

Class LzfEncoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelOutboundHandlerAdapter

io.netty.handler.codec.MessageToByteEncoder<ByteBuf>

io.netty.handler.codec.compression.LzfEncoder

All Implemented Interfaces:

ChannelHandler, ChannelOutboundHandler

public class LzfEncoder
extends MessageToByteEncoder<ByteBuf>

Compresses a ByteBuf using the LZF format. See original LZF package and LZF format for full description.

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field and Description
private com.ning.compress.lzf.ChunkEncoder	encoder Underlying decoder in use.
private static int	MIN_BLOCK_TO_COMPRESS Minimum block size ready for compression.
private com.ning.compress.BufferRecycler	recycler Object that handles details of buffer recycling.

Constructor Summary

Constructors

Constructor and Description
LzfEncoder() Creates a new LZF encoder with the most optimal available methods for underlying data access.
LzfEncoder(boolean safeInstance) Creates a new LZF encoder with specified encoding instance.
LzfEncoder(boolean safeInstance, int totalLength) Creates a new LZF encoder with specified settings.
LzfEncoder(int totalLength) Creates a new LZF encoder with specified total length of encoded chunk.

Method Summary

Modifier and Type	Method and Description
protected void	encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) Encode a message into a ByteBuf.

Methods inherited from class io.netty.handler.codec.MessageToByteEncoder

acceptOutboundMessage, allocateBuffer, isPreferDirect, write

Methods inherited from class io.netty.channel.ChannelOutboundHandlerAdapter

bind, close, connect, deregister, disconnect, flush, read

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, exceptionCaught, handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelHandler

exceptionCaught, handlerAdded, handlerRemoved

Field Detail

MIN_BLOCK_TO_COMPRESS

private static final int MIN_BLOCK_TO_COMPRESS

Minimum block size ready for compression. Blocks with length less than MIN_BLOCK_TO_COMPRESS will write as uncompressed.

See Also:

Constant Field Values

encoder

private final com.ning.compress.lzf.ChunkEncoder encoder

Underlying decoder in use.

recycler

private final com.ning.compress.BufferRecycler recycler

Object that handles details of buffer recycling.

Constructor Detail

LzfEncoder

public LzfEncoder()

Creates a new LZF encoder with the most optimal available methods for underlying data access. It will "unsafe" instance if one can be used on current JVM. It should be safe to call this constructor as implementations are dynamically loaded; however, on some non-standard platforms it may be necessary to use LzfEncoder(boolean) with true param.

LzfEncoder

public LzfEncoder(boolean safeInstance)

Creates a new LZF encoder with specified encoding instance.

Parameters:

safeInstance - If true encoder will use ChunkEncoder that only uses standard JDK access methods, and should work on all Java platforms and JVMs. Otherwise encoder will try to use highly optimized ChunkEncoder implementation that uses Sun JDK's Unsafe class (which may be included by other JDK's as well).

LzfEncoder

public LzfEncoder(int totalLength)

Creates a new LZF encoder with specified total length of encoded chunk. You can configure it to encode your data flow more efficient if you know the average size of messages that you send.

Parameters:

totalLength - Expected total length of content to compress; only matters for outgoing messages that is smaller than maximum chunk size (64k), to optimize encoding hash tables.

LzfEncoder

public LzfEncoder(boolean safeInstance,
                  int totalLength)

Creates a new LZF encoder with specified settings.

Parameters:

safeInstance - If true encoder will use ChunkEncoder that only uses standard JDK access methods, and should work on all Java platforms and JVMs. Otherwise encoder will try to use highly optimized ChunkEncoder implementation that uses Sun JDK's Unsafe class (which may be included by other JDK's as well).

totalLength - Expected total length of content to compress; only matters for outgoing messages that is smaller than maximum chunk size (64k), to optimize encoding hash tables.

Method Detail

encode

protected void encode(ChannelHandlerContext ctx,
                      ByteBuf in,
                      ByteBuf out)
               throws java.lang.Exception

Description copied from class: MessageToByteEncoder

Encode a message into a ByteBuf. This method will be called for each written message that can be handled by this encoder.

Specified by:

encode in class MessageToByteEncoder<ByteBuf>

Parameters:

ctx - the ChannelHandlerContext which this MessageToByteEncoder belongs to

in - the message to encode

out - the ByteBuf into which the encoded message will be written

Throws:

java.lang.Exception - is thrown if an error occurs